Current planned use cases are Pi Hole, Bitwarden (password manager) server, probably general network storage and torrenting, whatever other "homelab" things I think of later (which is why the specs probably seem a bit overkill)
Lenovo ThinkCentre mini desktop, eBay refurbished, $184 before tax
8GB RAM, 500GB SSD
Intel Core i5 6th Gen. (they don't specify but I'm assuming it's a 6000 series, which was released in 2016)
Direct link to the listing: https://www.ebay.com/itm/293526962748
Check out this one: https://www.ebay.com/itm/204486213478
It has an 8th gen CPU but smaller SSD. The CPU is also a T model. That particular one will mean your system will idle at around 10W of power, which is pretty fantastic.